If you plan on stealth camping, make sure you can use it with the slide in. Kind of hard to be stealthy when you have to open up the slide.
DW and I just completed a 4600 miles 4 week trip in our very small non-slide 815. We never had a problem or wished for more space, must less having a slide. IMO, the loss of cabinet space (most don't have a cabinet in the slide) nor the potential for problems are worth the few extra feet.
My fathers 3000 series bigfoot easily sits 4 at the dinnett, but his camper is 8'-6" wide. We did see an Artic Fox 865 on our trip which is a non-slide with dinette that could sit 4 if you don't mind be a bit snug, but it wouldn't be bad, only issue is the weight of the Artic Fox unit.